Shelf



FIG. 1 is a top perspective view of a shelf showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is an end elevational view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a partial top perspective view showing a corner portion thereof. 

The ornamental design for a shelf, as shown and described. 